As is commonly known, a wastegate valve is a type of control valve provided on a bypass passage for engine exhaust gas in a supercharger, and is for properly controlling a supercharging pressure of combustion air supplied to an engine. For example, a wastegate valve control device for a supercharger-equipped internal combustion engine disclosed in Patent Literature 1 below controls an air bypass valve when an abnormality has occurred in a drive mechanism for a wastegate valve and thereby copes with the abnormality.